Means for making a surgical cast



Dec. 10, 1968 z. D. SHELDON 3,415,243

} MEANS FOR MAKING A SURGICAL CAST Filed July 19, 1965 INVEN TOR ZACHARYD. SHELDON 8) MDW A T TORNEYS United States Patent (3 3,415,243 MEANSFOR MAKING A SURGICAL CAST Zachary I). Sheldon, Andover, Mass,assignorto Avco Corporation, Cincinnati, Ohio, a corporation of DelawareFiled July 19, 1965, Ser. No. 472,783 26 Claims. (Cl. 128-90) ABSTRACTOF THE DISCLOSURE An article of manufacture for use as a surgical castwhich includes a plurality of reagents which are reactive whenintermixed to form a hardenable cast material. The reagents are embodiedin a pliable sheet, preferably surgical gauze. The reagents aremaintained in a dormant state by virtue of the fact that one of thereagents is encapsulated within a rupturable material.

This invention relates to surgical casts, and more particularly to anarticle of manufacture for use as a surgical cast, and its method ofapplication.

Heretofore, surgical casts have generally been manufactured from aplaster of Paris material. The surgeon is required to mix plastermaterial with water to provide a moldable cast material at the site ofapplication of the cast.

The manufacture of these surgical casts is both a complex and oftenmessy process due to the variables involved in the operation and therequirement of handling the large quantities of wet plaster. Therefore,the need for providing a cast which is less diflicult to apply, andwhich requires no special talent in its proper application has long beenevident.

In the application of the common plaster of Paris cast, the mixture iseffected by temperatures of the water, quantity of water, and type ofplaster of Paris used. Taking these variables into consideration, it isapparent that the surgeon applying the cast must be skilled in the art,as an improper mix may result in excess heat being developed in theapplied cast, or a resultant cast of inferior quality.

In addition, the storage of plaster of Paris material presents a problemin that excessive moisture tends to react with the stored material, andthe shelf life is thereby limited unless appropriate precautionarymeasures are observed. The present invention therefore, has vas ageneral object to eliminate or minimize many of the objectionablefeatures found in prior art surgical cast, and provide an article ofmanufacture for use as a surgical cast which has a long shelf life.

A more specific object of the invention is to provide an article ofmanufacture for use as a surgical cast which provides a fail-proofmixture of the cast reagents in every application.

Another object of the invention is to provide an article of manufacturefor use as a surgical cast which is simple to manufacture, easilystored, and is easily applied.

A further object of the invention is to provide an article ofmanufacture for use as a surgical cast which article facilitatesapplication of a cast to a body member.

Still another object of the invention is to provide a method of forminga substantially rigid member, such as a surgical cast, which method iseasy to perform, and repeatable to obtain the required end result.

Still another object of the invention is to provide a method of forminga surgical cast which method may be performed with a minimum ofequipment, and with a minimum of experience or skill.

A more specific object of the invention is to provide an article ofmanufacture for use as a cast wherein at least one of the cast formingreagents is encapsulated in a rupturable material.

A 'further specific object of the invention is to provide a method offorming a cast wherein a hardening agent is positioned adjacent :amember by breaking an encapsulation whereby the hardening material isreleased.

Yet another object of the invention is to provide an article ofmanufacture for use as a cast wherein the cast forming reagents have amodifying agent interspersed therein.

One of the more recent technological developments has produced methodswhereby liquids, solids, or gases may be encapsulated within miniaturespheres. One such method is described in the US. Patent No. 3,155,590 toMiller et al. and assigned to National Cash Register Company.

The present invention advantageously employs this or other liketechnology to encapsulate one or more of the reagents or componentsnecessary to produce a cast material. The various components of thehardenable material are mixed in the dormant state, which dormancy ismaintained by encapsulating one or more of the reactive agents to keepthem separated.

The reagents are then placed on a carrier, generally a pliable sheet orgauze material. which may be rolled or folded into a compact article.

The method of utilizing the article to form a cast comprises merelybreaking the capsule material, applying the carrier to conform to theinjured body member, and allowing the material to become rigid.

The novel features that are considered characteristic of the inventionare set forth in the appended claims; the invention itself, however bothas to its organization and method of operation, together with additionalobjects and advantages thereof, will best be understood from the following description of a specific embodiment when read in conjunctionwith the accompanying drawings, in which:

FIGURE 1 is an elevational view showing an article manufactured inaccordance with the present invention which article is provided in theform of a rolled tape or bandage;

FIGURE 2 is a sectional view taken on the line 22 of FIGURE 1 showing ona greatly enlarged scale the elements of the present invention;

FIGURE 3 is a schematic view showing the article of the presentinvention being operated on during its :application;

FIGURE 4 is a schematic view showing an alternate embodiment of theoperation shown in FIGURE 3; and

FIGURE 5 is an elevational view showing an application of the articleshown in FIGURE 1 and taken on a smaller scale.

Referring now to the drawings especially FIGURES 1 and 2 there is shownan article 10 in the form of a rolled bandage or tape for use as asurgical cast material. The article 10 may be of .any suitable width andis compactly rolled for ease of handling. The length of the article 10is generally limited only by the desired weight of the roll.

As best shown in FIGURE 2, the tape or bandage provided by the article10 comprises a carrier 11, generally of pliable sheet material. Thecarrier 11 is preferably comprised of a liquid permeable material (forpurposes which will be evident as the description proceeds) and may befolded upon itself as shown in FIGURE 2, or may be of two separatesheets. A typical method of [fabricating the carrier :11 is to employ aplurality of surgical gauze sheets stacked one upon the other to adesired thickness, thus maintaining a closeness of weave which minimizesthe passage of solid particles therethrough.

The carrier 11 has disposed thereon a plurality of reagents 12 which arenormally dormant, but react when intermixed to form a hardenable castmaterial. Typical of such reagents 12 are the more commonly usedcalcined plaster of Paris and water.

Other materials which are useful for this purpose are a semiprepolymerbinding reagent and an activating reagent of polyol which may be apolyether derived from sorbitol and propylene oxide. The lattermaterials, when used, are quite effective to produce a lightweight cast,which is desired in most applications.

Referring still to FIGURE 2, it should be noted that the reagents 12 aresealed within a multiplicity of capsule elements 13 fabricated from arupturable material. The capsule elements 13 may be from 1 micron indiameter to A3" diameter and should be of a non-toxic material forsurgical applications when used in direct contact with the skin. Forexample, the elements 13 may be manufactured from polyethylene, gelatin,polypropylenes, silicons and Teflon or many other rupturable polymericmaterials.

As previously discussed, the utilizing of a plurality of layers ofsurgical gauze as a carrier 11 is effective to retain the capsules 13 inthe article 10. The capsules 13 are held in place by the inner strandsof the gauze material and are prevented from passing completely throughthe carrier 11 by the outer layers of gauze.

However, should it be desirable to use a single layer of cloth, or othermaterial for the carrier 11, the capsules 13 may be cemented in placeusing any relatively porous cementing material, for example a pasteformed of plaster of Paris and water.

Referring now to FIGURE 3, a pair of rollers 14 and 16 are schematicallyshown disposed in spaced relation such that the tape or bandage articlemay be fed therebetween, the rollers being so spaced as to cause arupturing force to be applied to the capsule elements 13 when passedtherebetween, thus releasing the reagents 12 from within the elements 13to intermix with other reagents and form the hardenable cast material.

In FIGURE 4 an alternate embodiment of the capsule breaking apparatus isshown. An infrared lamp 17 directs high-energy heat to the surface ofthe tape 10. The increase of temperature of the reagents 12 causes anincrease in vapor pressure within the capsules 13, and by carefullycontrolling the temperature, the spheres are broken by internal pressurewithout damage to the carrier 11.

To conclude the application of the cast to a body member, the tape orbandage 10 is placed adjacent the body member by wrapping as shown inFIGURE 5. By maintaining proper control over the temperature produced bythe reaction of the reagents 12, the tape 10 may be wrapped directly incontact with the body member immediately after crushing the reagentholding capsules 13. Control of the reaction temperature is generallymaintained by proportioning of the reagents 12, which is well known inthe art. However, as will be hereinafter set forth in detail, thepresent invention provides for adding a modifying media to the castforming material to absorb the heat of reaction, and thereby obtain thedesired result. Should it be desired to provide additional comfort tothe patient due to a delicate skin condition or other circumstance astocking or thin layer of gauze material may be applied to the memberjust prior to application of the tape 10.

The tape article 10 is generally wound with each successive layerover-lapping the preceding layer, and is passed first in one directionand back in the other to a desired thickness. The number of passes, andthe resultant thickness of the cast, may be varied according to theapplication, considering the materials used and the rigidity necessaryto restrain the member.

In addition to the reagents 12, the carrier 11 may be provided withvarious modifying agents such as porosity inducing media 18, thermalabsorbing elements 19, and/ or strengthening fibers 20. All of theseagents may be encapsulated to form uniformity of the cast producingmaterial or encapsulation may be restricted to include only thoseelements which react with one another, or react with air or moisture.

A porosity inducing medium 18 which is effective with plaster of Parisis ordinary cork, however, vermiculate or cotton linters may also beeffectively used. In addition, should the porosity inducing elements beencapsulated, as the reagents, a porosity may be induced by simplyencapsulating air.

As previously considered, many reagents useful as a cast formingmaterial may produce undesirable heat. To insure comfort to the patient,materials may be provided to absorb heat from the reaction of thereagents 12. The problem is easily handled in the present invention byincluding on the carrier 11 a thermal absorbent element 19, which alsomay be encapsulated. It is generally desirable to choose those thermallyabsorbent elements 19 which do not interfere with X-ray penetration ofthe cast. Metallic aluminum powder is a common material used for thispurpose, however, powders of magnesium, durel or boron nitride areequally effective in producing the desired result.

In the description of FIGURE 5 reference was made to providing athickness of cast which gives adequate strength to properly restrain thebody member.

One other method of increasing the strength of the cast is to includefibers 20 in the hardenable cast material. The fibers 20 may beencapsulated and intermixed with the reagents to produce a reinforcementof the material, or may be introduced in the uncovered form. For thispurpose, cotton linters are effective reinforcing agents, however, nylonfibers are also used for reinforcing purposes.

It should be understood from the foregoing that only those agents orreagents which are considered to have qualities requiring encapsulationneed be provided in capsule form. In practicing the present invention,one or all of the cast forming material constituents may beencapsulated.

For example, in the preparation of a cast forming material whereincalcined plaster of Paris, water and nylon strengthening fibers areused, only the water need be encapsulated to prevent reaction occuringprior to application of the cast. However, for the purpose of providinga more homogeneous material for mixing, and to prevent the reagents andagents from separating into layers when on the carrier, the water,plaster of Paris and nylon fibers may be provided in capsules ofsubstantially equal s1ze.

As a further example, the reagents 12 may comprise a mixture of elementswhich are not hardenable until exposed to air such as a common householdcement. In this example, the hardenable agent is encapsulated and may beemployed solely with the carrier to form a hardened cast.

From the foregoing description it should be concluded that the presentinvention provides an article of manufacture 10 which when formed into asurgical cast effectively overcomes many of the objectionable featuresof of prior art casts.

In addition, the various objects of the invention are further achievedby providing a cast material which is easily subjected to stringentquality control and analysis. By pre-mixing the reagents in the dormantstate, each batch of cast material may be tested as to thermal qualitiesduring reaction, porosity, absorption, and rigidity in the final form.These, and other qualities of the cast may be closely controlled byemploying the present invention.

It should also be evident that employment of a liquid permeable materialfor the carrier 11 in combination with porosity inducing media asdescribed allows the injured body member to breathe while the. cast isin place.

Also, the providing of a cast material which is applied as a tape orbandage, allows a more perfect adherence to the contour of the bodymember, which is one highly desirable feature of a surgical cast.

preferred embodiment illustrated, all of which may be achieved withoutdeparting from the spirit and scope of the invention as defined by thefollowing claims:

I claim:

1. An article of manufacture for use as a surgical cast which comprises:

a carrier comprised of surgical gauze material,

a plurality of dormant reagents disposed on said carrier, which reagentsare reactive when intermixed to form a hardenable cast material, and

a multiplicity of capsule elements of rupturable material, eachcontaining one of said reagents.

2. The article defined in claim 1 wherein one of said plurality ofreagents is calcined plaster of Paris and another of said reagents iswater.

3. The article defined in claim 1 wherein one of said plurality ofreagents is a semi-prepolymer and another of said reagents is a polyolactivator.

4. An article of manufacture for use as a surgical cast which comprises:

a carrier of pliable sheet material,

a plurality of domant reagents disposed on said carrier,

which reagents are reactive when intermixed to form a hardenable castmaterial,

a multiplicity of capsule elements of rupturable material eachcontaining one of said reagents, and

an agent having high thermal absorption qualities interspersed with saidcapsules.

5. The article described in claim 4 wherein said agent having highthermal absorption qualities is aluminum powder.

6. An article of manufacture for use as a surgical cast which comprises:

a carrier of pliable sheet material,

a plurality of dormant reagents disposed on said carrier, which reagentsare reactive when intermixed to form a hardenable cast material,

a multiplicity of capsule elements of rupturable material eachcontaining one of said reagents, and

a porosity inducing agent interspersed with said capsules.

7. The article described in claim 6 wherein said porosity inducing agentis cork.

8. An article of manufacture for use as a surgical cast which comprises:

a carrier of pliable sheet material,

a plurality of dormant reagents disposed on said carrier, which reagentsare reactive when intermixed to form a hardenable cast material,

a multiplicity of capsule elements of rupturable material eachcontaining one of said reagents, and reinforcing fibers interspersedwith said capsules.

9. The article described in claim 8 wherein said reinforcing fibers arecotton linters.

10. An article of manufacture for use as a surgical cast whichcomprises:

a liquid permeable carrier comprised of adjacent sheets of surgicalgauze,

a plurality of reagents disposed between said sheets of material, whichreagents are reactive when intermixed to form a hardenable castmaterial, and

a multiplicity of capsule elements of rupturable material eachcontaining one of said reagents.

11. An article as described in claim 10 wherein one of said plurality ofreagents is calcined plaster of Paris and another of said reagents iswater, and said water reagent is contained by said multiplicity ofcapsule elements.

12. An article as described in claim 10 wherein one of said plurality ofreagents is a semi-prepolymer and another of said reagents is a polyolactivator, said activator reagent being contained by said multiplicityof capsule elements.

13. A method of forming a surgical cast which comprises:

providing a plurality of reagents embodied within a carrier fabric whichare reactive when intermixed to form a hardenable cast material,maintaining said reagents dormant by providing at least one of saidreagents in the form of a multiplicity of particles encapsulated by arupturable material,

breaking said rupturable encapsulating material to release said onereagent into intermiring relation with the other of said reagents, and

applying the cast material to a body member.

14. A method of forming a surgical cast which comprises:

providing a plurality of reagents embodied within a carrier fabric whichare reactive when intermixed to form a hardenable cast material,

maintaining said reagents dormant by providing at least one of saidreagents in the form of a multiplicity of particles encapsulated by arupturable material, applying the cast material to a body member, andbreaking said rupturable encapsulating material to release said onereagent into intermixing relation with the other of said reagents.

15. A method of forming a surgical cast which comprises:

providing a carrier of pliable sheet material having a plurality ofreagents dispersed therein, which reagents are reactive when intermixedto form a hardenable cast material,

maintaining said reagents dormant by providing at least one of saidreagents in the form of a multiplicity of particles encapsulated by arupturable material,

breaking said rupturable encapsulating material to release said onereagent into intermixing relation with the other of said reagents, andapplying the cast material to a body member. 16. The method described inclaim 15 which further includes the step of providing spaced rollers,and wherein the breaking of said rupturable encapsulating material isaccomplished by passing said carrier between said spaced rollers.

17. The method described in claim 15 which further includes the step ofproviding a source of high heat energy and wherein the breaking of saidrupturable encapsulating material is accomplished by applying said heatenergy to said capsules causing said capsules to burst from internalpressure.

18. A method of forming a surgical cast which comprises:

providing a carrier comprising a pair of pliable sheets and a pluralityof reagents which are reactive to form a hardenable material disposedbetween said sheets, one of said reagents being in the form of a liquid,7

maintaining said reagents dormant by providing said liquid reagent inthe form of a multiplicity of capsule elements containing said liquid,

breaking said capsule elements to release said liquid reagent intointer-mixing relation with the other of said reagents, and

applying said carrier to a body member.

19. A method of forming a substantially rigid member which comprises:

providing a carrier of surgical gauze material having a plurality ofreagents disposed thereon which re agents are reactive when intermixedto form a hardenable material,

maintaining said reagents dormant by providing at least one of saidreagents in the forming a multiplicity of particles encapsulated byrupturable material, and

breaking said rupturable encapsulating material to release said onereagent into intermixing relation with the other of said reagents.

20. An article of manufacture for use as a surgical cast whichcomprises:

a carrier comprised of pliable sheet material,

a plurality of diminutive particles of difierent reagents disposed onsaid carrier, which reagents are reactive when intermixed and broughtinto contact to form a hardenable cast material,

means for maintaining said particles of different reagents physicallyseparated by maintaining said reagents in a dormant state, and

an agent interspersed throughout said reagents for modifying said castmaterial.

21. The article of manufacture described in claim 20, wherein saidmodifying agent is a porosity inducing media.

22. The article of manufacture described in claim 21 wherein saidporosity inducing media is cork.

References Cited UNITED STATES PATENTS 2,714,974 8/1955 Sawyer.3,027,336 3/1962 Gotz et a1. l2890 XR 3,048,169 8/1962 Pierce 128-903,208,102 9/1965 Rubio. 3,215,137 11/1965 Laakso 128 3,266,625 8/1966Hardman.

RICHARD A. GAUDET, Primary Examiner.

R. L. FRINKS, Assistant Examiner.

US. Cl. X.R.

